Once upon a time, when I were a lad, you got into Line Maintenance by getting kicked out of the workshops. I managed to get on The Line by systematically failing to get a single generator to pass the armature insulation resistance test in six weeks. (For the record, when cleaning an armature with unleaded petrol you can air blast the resulting carbon sludge well into the windings then crank the drying oven up to max temp. to bake it into a solid 300 ohm crust.
)
Today, as
PhilM says, you need at least an 'A' licence to be welcome out in the cold.
I'm intrigued about someone with an upper second wishing to work on the Line - it takes all sorts, I suppose. Its probably best not to mention the degree when trying for a job as an unlicensed mechanic. Once you've got into an airline or general aviation, do the practical experience and the theory exams to get the licence.
Yes, airlines do hire gaduate engineers, but usually in the Tech Support Services area.